1. Field of the Invention
Details of state-of-the-art adapters and test systems are disclosed in patents, DE-A-4010297, DE-A-4107767 and DE-P-4212837.
In the art of printed circuit board testing, it is common to use adapters which mainly consist of a support plate and contact elements set into this support plate. Spring-loaded contact elements, also known as spring-loaded probe assemblies, provide for electrical contact to a printed circuit board with predetermined contact locations.
Rigid contact elements, located in the same support plate, are sufficient to contact the spring-loaded contact points of the test system. There is usually a lateral offset between a contact point of the circuit board with reference to the related contact point of the test system, to which it is to be electrically connected. This connection is usually accomplished using a pair of contact elements. These contact elements are interconnected by means of a wire in "Short-Wire" technology. Adapters of so-called "Long-Wire" technology usually only have spring-loaded contact elements to provide contact with the contact points of the circuit board, and a longer wire or lead for connection. The ends of these leads merge into a contact block, which can be equipped with contact elements that are of similar design to contact elements used in a "Short-Wire" adapter. This invention, which will be described in more detail later, is also suitable for contacts at this side of the adapter, as well as for similar applications.
A particular adapter is specifically designed for a given circuit board and can in general only be used for that particular kind of circuit board. If the circuitry of the board is modified, then usually, at least the adapter has to be modified, unless it is economically advantageous to employ a new adapter. Costly parts of such adapters are the contact elements, in particular the spring-loaded contact elements. Also for ecological reasons, the ability to re-use such contact elements is desirable. There are state-of-the-art proposals for contact elements in a support plate, which are exchangeable, however they can be securely locked into place for practical application.
2. Description of the Prior Art
One prior art proposal is based on the idea that the contact elements in the support plate contain notches and these contact elements are locked by means of a locking plate that interlocks with these notches. Compared to exchanging contact elements that are driven or glued into the support plate, this already represents a substantial improvement.